Wisconsin stunned No. 5 LSU 16–14 in an upset that forces a serious re-evaluation of both team’s seasons and could have dire consequences for Tigers head coach Les Miles’s future. Here are three thoughts on the Badgers’ upset:

1. Same old Brandon Harris

LSU’s last drive sums up the Tigers’ situation at quarterback perfectly. Harris showed some potential, completing three of his first four passes for 30 yards to advance the ball into Wisconsin territory. And on the final play of the drive, he demonstrated his evasiveness to escape pressure in the backfield. But then…

It’s virtually impossible to explain what Harris saw as he fired a bullet right to Wisconsin safety D’Cota Dixon’s chest. The only explanation is that Harris just didn’t reset his feet after avoiding the sack and fired wildly. Regardless, that’s the kind of mistake that shouldn’t happen for a quarterback in his third year playing, and it makes it very hard to foresee why the Tigers should expect any better quarterback play this season than the uneven performance that has dogged the program for the past few years.

Harris finished the game 12 of 21 for 131 yards with a touchdown and two interceptions. Had his last throw not happened and had LSU instead gained a few more yards and kicked a game-winning field goal, the conversation could have centered on whether the junior had made enough progress for the Tigers to contend for an SEC title. Instead, he left a lasting reminder of what the answer to that question is.

2. Wisconsin’s defense makes the Badgers a threat in the Big Ten West

Harris’s struggles may be his own, but Wisconsin’s defense still put together a promising performance in its first game without coordinator Dave Aranda. Justin Wilcox’s unit shut out LSU in the first half, and the Tigers’ only scores came on a pick-six and a 41-yard drive set up by a Wisconsin fumble.

The Tigers couldn’t get anything going offensively before halftime, as even Leonard Fournette got off to a sluggish start. Fournette was consistently met with multiple defenders by the time he reached the line of scrimmage and entered halftime with just 35 yards. Not to be denied, he eventually found some room to run as LSU’s offensive line won battles in the trenches. Fournette finished with 138 yards, but the Tigers’ 4.3 yards per carry was their worst average since their loss to Arkansas last season and their third worst in the past two years.

Wisconsin’s offense was hardly a juggernaut Saturday, and new starting quarterback Bart Houston’s two interceptions were particularly costly (one was in the end zone, the other was returned for a touchdown). But despite those early season hiccups, Wisconsin prevailed because of its shutdown defense. The Badgers led the nation is scoring defense last year, and while a much more difficult conference schedule this year (at Michigan State, at Michigan, vs. Ohio State and at Iowa all before the end of October) makes repeating that feat unlikely, Saturday’s performance suggests Wisconsin should not be taken lightly in a wide-open Big Ten West race.

3. Les Miles’s seat, already pretty hot, just got blistering

Miles’s name appeared at or near the top of just about every preseason hot seat watch. The LSU coach survived a coup last season, but that didn’t buy him a lot of job security, just enough to return for this season. The same powerful people who wanted Miles out last year now have a whole lot of new fodder for why he needs to go. It’s been clear throughout the off-season that whether Miles would remain the Tigers’ coach hinged on whether he could coax better quarterback play from Harris to allow LSU to compete with Alabama for SEC supremacy. The early returns are not promising.

One game may seem much too small of a sample size to evaluate Miles’s coaching performance this season, and that is true. But that doesn’t mean it will matter. With LSU, Texas A&M, Texas and Auburn all potentially in the market for a new coach in the coming months, and with Houston’s Tom Herman likely to top the wish list of all four schools (LSU would presumably check in again to see if it could pry Jimbo Fisher away from Florida State, too), each school has a strong incentive to pull the trigger early to try to gain the upper hand in negotiations for Herman.

That’s not to say that Miles will be fired in the coming hours, but he absolutely needs to get off to a strong start in SEC play; otherwise he may not last long enough to get another chance to beat Nick Saban.

More College Football

We've Got Apps Too

Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide — from Peter King, Tom Verducci, Lee Jenkins, Grant Wahl, Andy Staples and more — delivered straight to you, along with up-to-the-minute news and live scores.